WO2017025953A1

WO2017025953A1 - Contact lens system for vision correction

Info

Publication number: WO2017025953A1
Application number: PCT/IL2016/050858
Authority: WO
Inventors: Yair Alster; Omer Rafaeli; Ofer Pintel
Original assignee: Pres-By Vision Ltd
Priority date: 2015-08-09
Filing date: 2016-08-04
Publication date: 2017-02-16

Abstract

A contact lens system is provided. The contact lens system includes a first lens configured for positioning over a cornea and a second lens positioned over the first lens and attached thereto via at least one elastic tether. The distance between the first lens and the second lens is 150 microns or less and the second lens is capable of translating over the first lens a distance of about 2-6 mm.

Description

CONTACT LENS SYSTEM FOR VISION CORRECTION

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a lens system and, more particularly, to a contact lens system which can be used to correct vision problems such as presbyopia.

Typical vision problems such as myopia (nearsightedness), hyperopia (farsightedness) or presbyopia (loss of accommodation and subsequent loss of near and intermediate vision) are readily correctable using eyeglasses. However, some individuals prefer contact lenses for vision correction due to an active life style or aesthetic preferences.

Contact lens wearers who become presbyopic with age require additional corrective lenses to allow both near, intermediate and distance vision. While glasses provide a good optical solution for presbyopic contact lens wearers, eyeglasses can be less desirable by contact lens wearers for convenience and aesthetic reasons.

In attempts to provide a solution to this problem, contact lens makers have developed multifocal lenses which simultaneously focus light from a range of distances via several focal regions and bifocal lenses that include two simultaneously distinct lens powers, a central region for correction of myopia and a surrounding region for correction of hyperopia. The latter lenses translate with respect to the optical axis of the eye to provide both near and far vision correction depending on the eye gaze angle.

While bifocal and multifocal lenses can correct presbyopia, translation of the bifocal lens with respect to the cornea - anywhere from 2-6 mm (significantly more than standard contact lenses that typically translate about 0 to 0.5 mm) - can cause irritation and significant discomfort to the user while simultaneous focusing of light from several distances - as is the case for multifocal lenses - requires the user to 'process' light coming in from several distances. Furthermore, anatomical variability with respect to the distance between the optical axis and lower lid margin necessitates individual fitting of lenses and patient adjustment to correctly align the near- vision correction region of the bifocal lens to the optical axis during near vision tasks.

The above problems of bifocal and multi-focal lenses can be theoretically traversed by using a two lens system in which a first lens is positioned on the surface of the cornea and a second, translatable lens is positioned over the first lens. However, providing a lens system in which an outer lens translates back and forth over a stable inner lens while maintaining the entire lens system stable on the eye can be a challenging task.

Thus, it would be highly advantageous to have a lens system capable of correcting presbyopia while being devoid of the above limitations.

SUMMARY OF THE INVENTION

The present invention successfully addresses the shortcomings of the presently known configurations by providing a lens system that includes a first lens positionable over a cornea and a second lens attached to the first lens via elastic tethers. The lens system is configured such that the second lens is translatable over the first lens without appreciable movement of the first lens over the cornea when the system is positioned in an eye and the eye is rotated up and down.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings: FIGs. la-b illustrate one embodiment of the lens system of the present invention with the outer (second) lens in a home position (Figure la) and in a translated position (Figure lb) with respect to the inner (first) lens.

FIGs. 2a-l illustrate several tether patterns which can be used to interconnect the lenses of the present lens system.

FIGs. 3a-f illustrate several approaches for attaching the elastic tether(s) to the inner and outer lenses.

FIGs 4a-d illustrate several cross sectional shapes of elastic tether.

FIG. 5 illustrate the frictional forces generated between the lenses and elastic tether when elongated by translation of the outer lens with respect to the inner lens.

FIGs. 6a-c illustrate bench testing of a prototype of the present lens system.

FIGs. 7a-b illustrate testing of a prototype lens system in a subject.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a lens system that can be used to correct visions in hyperopic, myopic or emmetropic individuals with presbyopia. Specifically, the present invention can be used to provide both near, intermediate and far vision while traversing comfort and usability problems of prior art bifocal and multifocal lenses.

The principles and operation of the present invention may be better understood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Individuals who are contact lens wearers and become presbyopic during their mid forties find out that their contact lenses do not provide adequate solution for both near and distance vision tasks. Multifocal contact lenses as well as translating lenses (both rigid and soft) are available commercially but have not gained significant market share. Multifocal contact lens reduce vision quality while bifocal lenses require significant fitting effort and cause significant discomfort in many individuals.

Approaches for traversing limitations of presently used bifocal lenses have been described in the prior art. For example, US20080097600 describes a movable ophthalmic lens system which includes a carrier positionable on a portion of an eye, and a movable ophthalmic lens arranged for movement over a surface of the carrier. The assembly is configured such that the movable ophthalmic lens is responsive to ocular movement so as to move in translatory motion over the surface of the carrier. Although this solution can in theory address comfort problems and provide near and far vision, it does not take into account the forces present in the eye environment (eyelid's normal and lateral forces, as well as adhesion forces between the carrier and cornea and lens and carrier).

Another problem of current alternating contact lens for presbyopia is correct fitting for the distance between Lower Lid Margin to the center of pupil (LLM-COP). If the LLM-COP is larger than the ridge to the bifocal transition line, the lens won't translate enough to provide full and clear near vision. However, if the LLM-COP distance is too small, the patient may experience double vision in both near and far vision (both focal distance are within the pupil area). Current bifocal contact lens solution require production of few sizes and matching to ensure correct fit, however, these lenses can still fail to provide adequate vision correction in clinical practice.

While reducing the present invention to practice, the present inventors have devised a contact lens system for correcting visions problems in, for example, presbyopic individuals. The present system includes a first lens positionable over the cornea and a second lens positionable over the first lens and attached thereto via one or more elastic tethers. The position, length and elasticity of the tether(s) are selected so as to enable the second lens to slide with respect to the first lens from a home position (e.g. centered, no/minimum tension in tether) to a translated position (e.g. gaze down position) thereby tensioning the tether(s), and return to the home position - at gaze forward - under the elastic return forces generated by the tensioned tether(s).

Thus, according to one aspect of the present invention, there is provided a contact lens system for correcting vision problems such as presbyopia with or without correcting for additional refractive errors. In addition such lens system can provide a solution for low (near) vision magnification. As used herein, the term "lens" refers to a light-passing element. The phrase "lens system" refers to two or more lenses that are formed from two or more attached surfaces. The lenses can be any shape and configuration and can have zero, negative or positive optical power as well as cylindrical power.

The lens system of the present invention includes a first (also referred to herein as inner or back) lens configured for positioning over a cornea and a second (also referred to herein as outer or front) lens positionable over the first lens and attached thereto via one or more elastic tethers (e.g. elastic strings).

While setting out to design the present lens system, the present inventors identified the following requirements for functionality:

(i) the inner lens should be stable over the cornea with little or no movement during use;

(ii) the outer lens should easily translate over the inner lens without causing substantial movement of the inner lens over the cornea;

(iii) attachment between the inner and outer lenses should enable movement of outer lens from a first position to a second position and facilitate movement of the outer lens from the second position to the first position;

Following testing of a prototype lens system (see Examples section hereinbelow), the present inventors identified several additional requirements for functionality:

(iv) attachment between the inner and outer lenses should result in minimal spacing (micrometers) between the lenses and yet provide substantial translation distances (millimeters);

(v) attachment between the lenses should take into account frictional forces between lenses and tethers during translation of the outer lens over the inner lens;

(vi) attachment between the lenses should not interfere with the field of vision during gaze forward and gaze down and take into consideration the direction of movement of outer lens over inner lens;

(vii) attachment between the lenses should stabilize both lenses as one integrated system and prevent significant rotation on the cornea; (viii) attachment between the lenses should not deform the optical zones of the lenses during translation;

(ix) attachment between the lenses should maintain wettability of the lenses over time; and/or

(x) attachment between the lenses should produce and elastic return force to rapidly return the front lens to the home position (within a second or less) without pulling the front lens under the lower eyelid.

In order to meet the above requirements, the present inventors designed a lens system which incorporates the following features:

(a) spacing between lenses of about 20-150 microns;

(b) a translation distance of outer lens over inner lens of about 2-6 mm;

(c) tether length of about 200-800 microns;

(d) tether material capable of elastically elongating 500% or more;

(e) tether attachment region internal to edge of both lenses;

(f) 50- 5000 tethers attached in a specific pattern surrounding optical regions during gaze down and gaze forward, the pattern is selected for guiding movement of the outer lens over the inner lens;

(g) tether characteristics [cross sectional shape, surface qualities (e.g. roughness, stickiness), material, modulus of elasticity] selected so as to control friction between tether and lenses during elastic elongation of tether;

Referring now to the drawings, Figures la-5 illustrate the present lens system which is referred to herein as system 10.

System 10 includes an inner lens 12 attached to an outer lens 14 via one or more tethers 16 (two shown). Tethers 16 are fabricated from an elastic material capable of elastically elongating by at least 500%. Tethers 16 are attached to an outer surface 18 of lens 12 and an inner surface 20 of lens 14 by: forming tether 16 from an adhesive applied to lens 12 and/or lens 14 (Figure 3), co-molding tether 16 with lens 12 and/or lens 14 (Figure 3ab), molding Figure 3b, threading tether 16 through the material of lens 12 and/or lens 14 (Figure 3c), bonding tether 16 to a surface of lens 12 and/or lens 14 (Figure 3d) using a silicon -based adhesive , or mechanically attaching tether 16 to lens 12 and/or lens 14 by embedding a flat (Figure 3e) or wedge (Figure 3f) -shaped end region of tether 16 within (or through) the wall of lens 12 and/or lens 14.

Tether 16 can be fabricated from any material capable of elastic elongation in the ranges specified. Suitable materials include silicone (e.g. Shore 20-100), a modified silicone (e.g. fluoro-silicone) or a polyether block amide (PEBA).

Tether 16 is preferably 200-800 microns in length and 50-250 microns in diameter. Tether 16 is configured and/or attached between lenses 12 and 14 such that a distance therebetween (lens spacing) is 20-150 microns. Tether can be linear and attached at an angle between outer surface 18 of lens 12 and an inner surface 20 of lens 14 (e.g. an angle of 0-45 degrees) or it can be non-linear (e.g. the curved strut shown in Figure la) and attached at a substantially perpendicular angle. In the latter case, a tether 200 microns in length can be curved and attached substantially perpendicularly (90 degrees +/- 20%) to outer surface 18 of lens 12 and an inner surface 20 of lens 14 (as is shown in Figure la) to space apart lenses 12 and 14 by about 120 microns.

Tether 16 can be configured such that elastic elongation thereof is uniform or not. In a non -uniform elongation, tether 16 may progressively become easier or harder to stretch. For example, tether 16 may require less force to stretch to a first length (e.g. 75% of final length) and more force to stretch from the first length to a final length.

Figure la illustrates tethers 16 in a non-elongated state when lens 14 is in a home position over lens 12. When in the home position, the optical centers of lenses 12 and 14 do not co-align at optical axis 28 which runs through a non-optical center region of lens 14 and an optical region 24 of lens 12. This is the case during gaze forward (Figure la, inset - top left) when lens 12 provides far vision correction and lens 14 merely allows transfer of light with no optical correction of region 26. During gaze down (Figure lb, inset - top right), lens 14 translates up over lens 12, elastic tethers 16 elongate, and optical centers 24 and 26 (of lenses 12 and 14 respectively) align to provide near vision correction. Lens 14 translates up during eye roll down (at gaze down) under the forces applied by the rim of lower lid to lens 14. These forces overcome the elastic force of tethers 16 and the frictional forces between lenses and tethers 16 (further discussed hereinbelow). To direct the forces of a lid rim lens 14 can include a lid engagement element 30 (protrusion shown in Figure la, or high friction region) to engage the rim or inner surface of the lower lid during gaze down. Lid engagement element 30 would increase the lateral forces applied to the second lens by the lower lid thus further contributing to the forces that overcome elastic recoil of tethers 16 and friction between lenses and lenses-tethers.

Any number of tethers can be attached between lenses 12 and 14. For example, 50-5000 tethers 16 can be attached between lenses 12 and 14 in a patterns that surrounds optical regions 24 and 26 of these lenses and provides a guide path for lens 14 as it translates over lens 12. Figures 2b-l illustrate several such patterns of tethers attached between lenses 12 and 14 (indicated in Figure 2a).

Figure 2b-c illustrates a discontinuous (Figure 2b) or continuous (Figure 2c) circle pattern formed by a plurality of adjacent tethers positioned between lenses 12 and 14. Figure 2d illustrates a discontinuous circle pattern formed by spaced apart tethers. Figure 2e illustrates four tethers positioned along a circumferential region of lens 134. Figure 2f illustrates two segments of 5 tethers each positioned symmetrically across a 45 degree line dividing lens 14. Figure 2g illustrates an arc-shaped pattern formed from 10 tethers at bottom of lens 12. Figure 2h illustrates a 10-tether circular pattern positioned along a circumferential region of lens 14. Figure 2i illustrates a 4 tether pairs pattern positioned at the four corners of an imaginary square superimposed on lens 14. Figure 2j illustrates an arc pattern formed from 10 tethers and positioned at the top of lens 14. Figure 2k illustrates a pattern similar to that of Figure 2i with the tethers adjacent to one another. Figure 21 illustrates a pattern formed from adjacent and spaced apart tethers positioned along a circumferential region of lens 14.

Since the pulling forces of tether 16 can distort the lens surface at the point of attachment and lead to optical distortion or destabilizing of lens 12 on the cornea, the region and pattern of attachment of tethers 16 are also selected such that elongation of tethers 16 does not deform the shape of lenses 12 and 14 or affect the optical focusing capabilities thereof or stability of lens 12 on the cornea.

The cross sectional shape of tether 16 can be uniform or varying over its length. The cross sectional shape can be circular (Figure 4a), rectangular (Figure 4b), triangular (Figure 4c) or ovoid (Figure 4d) and any combination thereof. Likewise, the thickness of tether 16 can be uniform or variable over a length. The cross sectional shape and thickness are selected so as to control the frictional forces between tether 16 and outer surface 18 of lens 12 and inner surface 20 of lens 14 so as to control movement of lens 14 over lens 12 during translation at gaze down and (elastic) return at gaze forward. For example, a tether 16 having a round cross section with a diameter of 100 μπι (Figure 5), will ovalize when stretched and trapped between surfaces 18 and 20. Such ovalization will increase surface friction between tether 16 and surfaces 18 and 20.

For example, a rounded tether will ovalize when compressed between lenses 12 and 14 and as such its co-efficient of friction will change and should be taken into consideration when optimizing tether over all structure, cross section and material.

In addition, the materials, coatings, shapes and dimensions of lenses 12 and 14 are also selected so to control translation of lens 14 and stability of lens 12.

The materials of lenses 12 and 14 and/or coatings of their surfaces (inner and outer surfaces of these lenses) can be selected such that the interface between lens 12 and the cornea and lenses 12 and 14, as well as the interface between lenses 12 and 14 and inner lid surfaces (lower and upper lid) exhibit a differential (static) coefficient of friction (CoF). Materials suitable for fabrication of the lenses include, but are not limited to hydrogel materials such as tefilcon, lidofilcon B, etafilcon, bufilcon A, tetrafilcon A surfilcon bufilcon A perfilcon crofilcon lidofilcon A deltafilcon A etafilcon A dimefilcon ofilcon A, droxifilcon A, ocufilcon Bhefilcon A & B xylofilcon A, phemfilcon A, phemfilcon A, phemfilcon A scafilcon A, ocufilcon, tetrafilcon B, isofilcon, methafilcon, mafilcon, vifilcon A,polymacon with the use of monomers such as HEMA, MMA, NVP, PVP, MA, PC, Modified PVA, PVA. Silicone Hydrogel materials can also be used such as but not limited to Balafilcon A or Lotrafilcon A with monomers such as NVP, TPVC, NCVE, PBVC, DMA, TRIS, siloxane macromere. Furthermore, rigid permeable gas contact lens material or pure silicone lenses can be used. Silicone can be made at different rigidities ranging from Silicone Shore A 10 to silicone Shore A 95. Such materials can be selected to provide the differential friction between the lenses of the present system or selectively coated with various material in order to meet such frictional constraints. Such materials can be further undergo surface treatment such as but not limited to plasma oxidation or include internal wetting monomers such as but not limited to PVP.

For example, the inner surface lens 12 can be fabricated from a material (e.g. Silicone) having a relatively high static CoF (against the cornea) to thereby increase the CoF of the first interface (between inner surface of lens 12 and cornea) and the resistance of lens 12 to lateral forces applied by the lids. The second lens can be fabricated from a material (e.g. Hydrogel) having a relatively low CoF (against the outer surface of the first lens) such that the second interface exhibits a static CoF which is lower than that of the first interface. This will ensure that the second lens translates over the first lens in the eye while the first lens remains stable. Another approach for decreasing the static CoF of the second interface is to fabricate the outer surface of lens 12 from a hydrophilic material (e.g. hydrogel) and at least the inner surface of lens 14 from a hydrophobic material (e.g. silicone).

The lenses can be composed of the same material with different surface treatment. The two lenses can also be of different materials. Also, each lens can also have one layer that is made of one material (e.g. Hydrogel) and another layer made of another material (e.g. Silicone). The contact area of any lens with its opposing surface can have similar properties over the entire contact area or it can have an area with one set or properties and at least one more area with different set of properties. Such properties can be achieved with combinations of materials, layers, coatings or surface treatments or roughness. The surfaces can also have mixed hydrophobic and hydrophilic properties in different zones, for example hydrophobic surface with hydrophilic islands where a fluid droplet makes contact with the surface only at small isolated regions, prevent adhesion and reduce friction [K Hiratsuka, Journal of Physics: Conference Series 89 (2007)].

The size of lenses 12 and 14 can be selected such that the ratio between the surface area of the first interface and that of the second interface ensures that the force of friction created by the first interface is much higher than that created by the second interface. For example first lens can be of standard size of about 14mm in diameter and second lens can have a diameter of about 7mm. Another example as has been provided above would be to have the first lens have a diameter of 16 mm and the second lens have a diameter of about 12 mm. In any case, a ratio of 5: 1 to 1.5: 1 between the area of the first lens and second lens (respectively) can be used to achieve differential translation of the second lens.

Lens 14 can be made more rigid, such rigidity can be achieved using rigid gas permeable contact lens material or silicone with higher shore A such as Silicone shore A 60 or above.

As is mentioned hereinabove, each of lenses 12 and 14 can have zero optical power, a positive optical power or a negative optical power with each lens having one or more optical centers. For example, lens 12 can have a single optical center with negative optical power for far vision correction (e.g. -1.0 to -5.0 Diopters), while lens 14 can have a single optical center with positive optical power for near vision correction (e.g. +1.25 to +4.0 Diopters) or two or more optical centers with positive optical powers for intermediate and near vision corrections. Lenses 12 and 14 can also have cylindrical powers (different vertical and horizontal powers).

The present lens system can be fabricated using well known approaches such as injection molding, vacuum forming, machining and the like. Approaches used for fabricating multifocal lenses can also be used in the present invention. Each lens 12 and 14 can be fabricated separately or both lenses 12 and 14 can be fabricated along with tethers 16 using overmolding techniques.

Coating of materials on the inner and outer surfaces of lenses 12 and 14 can be effected using plasma deposition and the like.

As used herein the term "about" refers to 10 % margins.

Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting.

EXAMPLES

Reference is now made to the following example, which together with the above descriptions, illustrate the invention in a non limiting fashion.

Prototype Two Lens System

Several prototypes of a two lens system for presbyopia correction were constructed and tested on a model of an eye and in subjects.

Materials and Methods

Two lenses, a back lens made of silicon with an optical power -3D, external diameter 14mm and 8.5 BC, and a front lens made of SH74 with optical power of 2D, outside diameter of 14.5 mm and 8.9BC were interconnected using two tethers attached at a vertical or horizontal orientation (side by side or top bottom respectively). Attachment to the front surface of the back lens was zero (tether flat with surface of back lens), 45 or 90 degrees.

In total 6 prototypes were fabricated: vertical-zero, vertical-45 and vertical-90 attachment and horizontal-zero, horizontal-45 and horizontal-90.

These 6 prototypes were tested on a model of an eye (model shown in Figures 6a-c) for stability and translation of front lens over back lens from a home position to a gaze down position and back.

Results

A vertical connection at the front lens and a 45 or 90 degree connection at the back lens was less effective and lead to local deformation of the lenses.

A lens system with a horizontal connection at the front lens (two tethers positioned at top and bottom) and a 0, 45 or 90 degree connection at the back lens was less functional since the tension in the tethers was different at different positions of the front lens over the back lens. For example, when the front lens was manually shifted to the near sight position (gaze down), the tension in the bottom tether increased while the tension in the top tether decreased.

A lens system in which the tethers were attached side by side (vertical) with a zero degree attachment at the back lens was utilized for further testing on the model and human eye.

The lens system was placed over the eyeball model and friction and movement were evaluated when the front lens was manually translated over the back lens. A force of a few grams was needed to move the front lens 4mm from home position on top of the back lens; when that force was removed, the front translated back to the home position in about a second. Translation was smooth and uninterrupted. The lens system was then tested in an eye of a human subject (Figures 7a-b). The lens system was placed in a human eye for 15 minutes and comfort, translation, movement and rotation were evaluated.

The subject reported that the lens was comfortable; observed translation was smooth and effective on gaze down and back to gaze forward and occurred in less than 1 second. No rotation was observed and local minimal deformation was seen in tether attachment-regions, with no deformations observed at the optical zones.

Conclusions The elastic tethers enabled translation of the front lens over the back lens with up to 4 mm of movement. Restoration to the home position under an elastic return force of the tethers was rapid with no perceivable affects on the optical qualities of both lenses.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A contact lens system comprising a first lens configured for positioning over a cornea and a second lens positioned over said first lens, wherein an outer surface of said first lens and an inner surface of said second lens are interconnected via at least one elastic tether such that a distance between said outer surface of said first lens and said inner surface of said second lens is 150 microns or less and said second lens is capable of translating over said first lens a distance of about 2-6 mm.

2. The contact lens system of claim 1 , wherein said elastic tether is capable of elastic elongation of at least 500%.

3. The contact lens system of claim 2, wherein a resistance coefficient of said elastic tether is constant throughout said elastic elongation.

4. The contact lens system of claim 2, wherein a resistance coefficient of said elastic tether increases or decreases throughout elastic elongation.

5. The contact lens system of claim 2, wherein a resistance coefficient of said elastic tether decreases or increases throughout elastic elongation of said elastic tether.

6. The contact lens system of claim 1, comprising 500-5000 elastic tethers.

7. The contact lens system of claim 1, wherein said at least one elastic tether is 200- 800 microns in length.

8. The contact lens system of claim 1, wherein said at least one elastic tether is 50- 250 microns in diameter.

9. The contact lens system of claim 1, wherein said first lens and/or said second lens each include an optical region of non-zero optical power.

10. The contact lens system of claim 9, wherein said at least one elastic tether interconnects said first and said second lenses at non-optical regions.

11. The contact lens system of claim 6, wherein said elastic tethers are attached at constant or variable intervals to form a closed or open pattern.

12. The contact lens system of claim 1, wherein said at least one elastic tether has a variable diameter along a length thereof.

13. The contact lens system of claim 1, wherein a cross sectional shape of said at least one elastic tether is round, square, elliptical or triangular.

14. The contact lens system of claim 13, wherein said cross sectional shape changes during elastic elongation of said at least one tether.

15. The contact lens system of claim 1, wherein a cross sectional shape of said at least one tether is selected such that elongation of said tether increases or decreases friction between said at least one tether and said first lens and/or said second lens.

16. The contact lens system of claim 1, wherein said at least one elastic tether is attached at a region 2 to 7 mm from a center of said first lens.

17. The contact lens system of claim 1, wherein attachment of said at least one elastic tether to said first lens is configured such that elastic elongation of said at least one tether does not substantially deform said first lens when mounted on a cornea.

18. The contact lens system of claim 1, wherein attachment of said at least one elastic tether to said first lens is configured such that elastic elongation of said at least one tether does not substantially impact an optical quality of said first lens when mounted on a cornea.